A new indole-diterpene, JBIR-03 (1), was isolated from the fungus Dichotomomyces cejpii var. cejpii NBRC 103559 and its structure was determined based on the spectroscopic data. 1 exhibited anti-MRSA (methicillinresistant Staphylococcus aureus) activity and antifungal activity against apple Valsa canker-causing fungus, Valsa ceratosperma, while it exhibited no toxicity towards human cancer cells.

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A new polypropionate alloaureothin (1) possessing a nitro group, together with a known polypropionate aureothin (2), was isolated from mycelium of Streptomyces sp. MM23. The structure was determined on the basis of spectroscopic data. 1 exhibited growth inhibitory effect against human fibrosarcoma HT1080 cells with an IC 50 value of 30 mM.Keywords polypropionate, alloaureothin, Streptomyces sp., cytotoxic Polypropionates with a nitro group, a class of polyketides, were isolated from several actinomycetes and displayed interesting biological activities. Aureothin (2) isolated from the mycelium of Streptomyces thioluteus [1] was reported to exhibit antifungal, antitumor, and anti-Helicobacter pylori activities [2]. Spectinabilin (3) isolated from the culture broth of Streptomyces spectinabilis [3] showed inhibitory activity against reverse-transcriptase in Rausche leukemia virus and antimalarial activity [4]. In the course of our screening program for biological active compounds of microbial origin, we isolated a new aureothin derivative, designated as alloaureothin (1), from mycelium of Streptomyces sp. MM23 (Fig. 1).The Streptomyces sp. MM23 isolated from soil sample collected in Hiroshima Prefecture, Japan, was cultured at 27°C for 5 days in 500-ml Erlenmeyer flasks containing a medium consisting of 2.5% starch, 1.5% soy bean meal, 0.2% dry yeast, 0.4% CaCO 3 (pH 6.2 before sterilization). The whole culture broth (2 liters) was centrifuged, and the mycelial cake was extracted with acetone (400 ml). The extract was evaporated in vacuo, and the residual aqueous concentrate was extracted with ethyl acetate. The organic layer (157 mg) was separated by silica gel flash column (Purif-Pack SI-60, Moritex) with a n-hexane -ethyl acetate linear gradient system (0ϳ100% EtOAc). The 50ϳ100% EtOAc eluate was further purified by reversed-phase HPLC (70% aqueous MeOH) with Senshu Pak PEGASIL ODS column (20 mm i.d.ϫ250 mm) to give a new compound 1 (Rt 38.8 minutes, 2.5 mg) and 2 (Rt 41.8 minutes, 8.3 mg) [1]. In both isolation procedures, peak detection was carried out by UV absorption at 254 nm. A structurally

We examined the biological activities present in Streptomyces strains preserved at the National Institute of Technology and Evaluation Biological Resource Center, and found a metabolite of Streptomyces roseolilacinus NBRC 12815 that showed a potent anti-tyrosinase activity. The compounds with anti-tyrosinase activity were purified by several chromatographic procedures. Final HPLC analysis revealed at least two anti-tyrosinase compounds with different retention times (12815A and B). The identification of two anti-tyrosinase compounds was performed with instrumental analysis and database search. The results obtained suggest that the active compounds are SF 2583A and B. Compound 12815A (IC 50 values; about 9 m mM) showed more potent tyrosinase inhibition than compound 12815B (IC 50 values; about 1086 m mM). The only structural difference between 12815A and B is the presence of an additional chloric atom. In addition, the activity of 12815A was markedly decreased under acidic conditions, resulting in irreversible inactivation. However, the inactivated 12815A still exhibited residual activity when exposed to detergent, Tween 80. These results suggest that the chlorine and the hydration water are very important in the exertion of anti-tyrosinase activity by 12815A.

A new member of the piericidin family, JBIR-02, was isolated from mycelium of Streptomyces sp. ML55 together with two known piericidin derivatives, piericidin A 1 and IT-143-B. The structure was determined on the basis of spectroscopic data. JBIR-02 inhibited nuclear export of b-arrestin in HeLa cells at the concentration of 20 mM.